Influence of microwave irradiation on kinetics and thermodynamics of extraction of flavonoids from <i>Phyllanthus emblica</i>

Krishnan, R. Yedhu; Rajan, K. S.

doi:10.1590/0104-6632.20170343s20150628

R. Yedhu Krishnan

Centre for Nanotechnology & Advanced Biomaterials (CeNTAB) School of Chemical & Biotechnology, SASTRA University, Thanjavur - 613401, India.

K. S. Rajan ^**Corresponding author: Email ksrajan@chem.sastra.edu, Telephone: 919790377951, Fax: 91 4362 264120

Centre for Nanotechnology & Advanced Biomaterials (CeNTAB) School of Chemical & Biotechnology, SASTRA University, Thanjavur - 613401, India.

*Corresponding author: Email ksrajan@chem.sastra.edu, Telephone: 919790377951, Fax: 91 4362 264120

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Figure 1
Experimental set for microwave-assisted extraction.

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Figure 2
Influence of extraction time on the concentration of flavonoids during MAE carried out at the solvent-to-feed ratio of 40 mL/g.

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Figure 3
Application of the second order model for the kinetics of MAE.

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Figure 4
Suitability of the diffusion model for MAE of flavonoids from P. emblica.

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Figure 5
Influence of solvent-to-feed ratio on the equilibrium concentration at T=40 °C and T= 100 °C for MAE.

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Figure 6
Influence of solvent-to-feed ratio on the equilibrium yield at T=40 °C and T=100 °C for MAE.

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Figure 7
Effect of solvent-to-feed ratio on initial extraction rate at T=40 °C and T=100 °C for MAE.

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Figure 8
Effect of temperature on the equilibrium concentration at S=5 mL/g and S=40 mL/g for MAE.

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Figure 9
Effect of temperature on the initial extraction rate at S=5 mL/g and S=40 mL/g for MAE.

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Figure 10
Determination of the activation energy for extraction.

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Figure 11
Applicability of Eq. (17) in predicting the new kinetic data.

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Table 1
Physical properties of water used for the extraction.

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Table 2
Details of the full factorial experimental design.

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Table 3
Uncertainty in the measurements.

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Table 4
Kinetic parameters (h, k) and Cs of the second order model for MAE at the solvent-to-feed ratio of 40 mL/g.

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Table 5
Kinetic parameters (h, k) and Cs of the second order model for CE at the solvent-to-feed ratio of 40 mL/g.

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Table 6
Effective diffusion coefficient for MAE and CE of flavonoids from P. emblica at a solvent-to-feed ratio of 40 mL/g.

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Table 7
Mass transfer coefficient and Biot number for MAE of flavonoids from P. emblica at a solvent-to-feed ratio of 40 mL/g.

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Table 8
Thermodynamic parameters for MAE of flavonoids from P. emblica.

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Table 9
Thermodynamic parameters for CE of flavonoids from P. emblica.

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Table 10
Composition of the aqueous extract of P. emblica fruits at T=40 °C and T=100 °C.

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14)

(15)

(16)

(17)

Property	Value
Electrical conductivity	6.8 µS/m
Thermal conductivity	0.6 W/(m K)
Density	1005 kg/m³
Viscosity	7.8×10^-4 N s/m²

Run Numbers	A: Solvent-to-feed ratio Level (Value in mL/g)	B: Temperature Level (Value in °C)	C_s (mgQE/mL)
1, 28, 34	4 (40)	4 (100)	0.38±0.01
2, 7, 42	4 (40)	3 (80)	0.34±0.00
3, 19, 43	4 (40)	1 (40)	0.28±0.00
4, 33, 48	1 (5)	2 (60)	0.58±0.00
5, 11, 15	2 (10)	1 (40)	0.41±0.00
6, 18, 24	3 (20)	1 (40)	0.37±0.01
8, 30, 38	3 (20)	4 (100)	0.54±0.00
9, 21, 32	1 (5)	3 (80)	0.64±0.00
10, 22, 47	1 (5)	1 (40)	0.52±0.00
12, 31, 37	2 (10)	3 (80)	0.54±0.02
13, 35, 44	2 (10)	4 (100)	0.67±0.01
14, 23, 27	1 (5)	4 (100)	0.79±0.00
16, 20, 25	4 (40)	2 (60)	0.32±0.00
17, 39, 40	3 (20)	3 (80)	0.47±0.01
26, 29, 45	3 (20)	2 (60)	0.41±0.01
36, 41, 46	2 (10)	2 (60)	0.47±0.01

Measurement	Uncertainity
Temperature	±1 °C
Mass of feed	±1 mg
Flavonoid concentration	±10 µg/mL

T (°C)	Cs (mgQE/mL)	h (mgQE/mL.min)	k (mL/mgQE.min)	R2
40	0.28±0.00	0.81±0.03	9.98±0.47	0.99
60	0.32±0.00	1.29±0.10	12.48±0.82	0.99
80	0.34±0.00	1.76±0.05	14.56±0.20	0.99
100	0.38±0.01	2.34±0.03	15.89±0.41	0.99

T (°C)	Cs (mgQE/mL)	h (mgQE/mL.min)	k (mL/mgQE.min)	R2
40	0.28±0.00	0.16±0.05	2.08±0.13	0.99
60	0.30±0.00	0.21±0.05	2.35±0.04	0.99
80	0.33±0.00	0.32±0.07	2.85±0.08	0.99
100	0.35±0.00	0.42±0.09	3.29±0.20	0.99

T (°C)	MAE		CE
	De×1011 (m2/s)	R2	De×1011 (m2/s)	R2
40	1.15±0.02	0.98	0.63±0.06	0.99
60	1.74±0.01	0.99	0.69±0.03	0.97
80	1.95±0.02	0.98	0.82±0.05	0.97
100	2.08±0.10	0.98	0.86±0.02	0.99

T (°C)	KT ×105 (m/s)	Bi
40	1.26±0.23	73.26±2.28
60	2.21±0.00	82.06±1.23
80	2.74±0.00	92.14±0.44
100	3.24±0.10	106.56±3.59

T (K)	Ke	∆H° (kJ/mol)	∆S° (J/mol.K)	∆G° (kJ/mol)
313	1.11	12.25	39.96	-0.25
333	1.46			-1.05
353	1.79			-1.85
373	2.43			-2.65

T (K)	Ke	∆H° (kJ/mol)	∆S° (J/mol.K)	∆G° (kJ/mol)
313	1.09	9.53	30.93	-0.15
333	1.26			-0.76
353	1.59			-1.38
373	1.94			-2.00

Compounds	% Peak area
	MAE		CE
	40 °C	100 °C	40 °C	100 °C
4H-Pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-	0.68	1.04	0.63	1.02
2-Furancarboxaldehyde, 5-(hydroxymethyl)-	4.28	4.46	6.11	8.37
Benzene, 1,1'-(1-methylethylidene)bis [4-methoxy-	4.38	10.21	2.81	6.70
1,2,3-Benzenetriol	63.27	51.57	62.24	57.47
D-Allose	7.45	21.89	10.19	12.94
1,6-Anhydro-α-d-galactofuranose	1.81	1.58	1.91	3.20
Other minor compounds	18.09	9.22	16.08	10.26

[1] *Corresponding author: Email ksrajan@chem.sastra.edu, Telephone: 919790377951, Fax: 91 4362 264120

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Influence of microwave irradiation on kinetics and thermodynamics of extraction of flavonoids from Phyllanthus emblica

Abstract